The present invention concerns both the apparatus for and a method of generating power in slow moving fluid streams, and particularly as a part of a free-flow, dam-less, hydropower generation system.
In the past few years, researchers at Marine Current Turbines Ltd. in the United Kingdom have deployed a demonstration unit to generate power from tidal flows. In Italy, trials using cross-axis turbines have demonstrated the feasibility of generating power from tides in the Messina straits. However, no commercial installations have yet been deployed.
The need for power is on the increase and this need influences the feasibility of generating electricity using cost-effective techniques, from a variety of water sources and especially from non-tidal, direct flowing waters in man-made canals, aqueducts, tailraces, diversion channels, or other fluid flow channels, is very desirable. The driving impetus for this undertaking is the recognition that there exists an enormous, worldwide potential for the conversion of kinetic energy existing in the water moving in canals, aqueducts, tailraces, diversion channels, or other fluid flow channels, into useful hydroelectric power. At the present time this potential for power generation remains untapped.
The present invention addresses the unique challenges inherent in the cost-effective extraction of hydroelectric power from slow moving waters, especially in man-made conveyance systems. First and foremost, since the primary function of these water conveyance systems is the conveyance of water for drinking or irrigation purposes, it is imperative that the installation and operation of a power generation facility in these slow moving waterways must not have an adverse impact on their capability to deliver water in a desired flow and at an expected quality. In the past, power generation or power output from relatively low flow or low velocity fluid flow channels, designed to operate at slow speeds to prevent scour or turbulence in the channel, was viewed as being too small to be cost-effective. What the present invention recognizes is that the otherwise slow flow velocities can be accelerated in the waterways beyond a lower threshold limit, and specifically at a designed location, or power generation zone, along the waterway where the kinetic hydropower system will be installed.
The present invention is based upon a design philosophy and criteria for a flume system that will accomplish this objective cost effectively, and without adversely impacting the primary function of these waterways, i.e., to convey water for drinking or irrigation purposes.
A vertical-axis turbine candidate technology is identified and briefly evaluated for potential deployment in the flume-enhanced flows of canals, aqueducts, tailraces, diversion channels, and other fluid flow channels to generate power cost-effectively. For example, a vertical axis, 6-ft diameter system, deployed in conjunction with a flume according to the present invention, can generate more than 20 KW in a typical 20 foot wide open channel environment.